The liquid crystal display devices, such as liquid crystal televisions, have been increased in size. However, as the size increases, there exists a problem that fuzziness of the image (also referred to as “motion blur” hereinafter) is obvious when a motion video is displayed.
To suppress motion blur, a method performing backlight scanning has been known. The backlight scanning means sequentially pulse-lighting a plurality of backlights (light source) toward a group of liquid crystal pixels of the display panel in the line direction. In the present disclosure, an effect suppressing motion blur is shortly called a scan effect.
For such backlight scanning, technology to correct luminance dispersion of each backlight has been known (e.g. Patent Document 1).
Patent Document 1 describes that each backlight may be arbitrarily dimmed by supplying each backlight with a drive current that is pulse-width modulated based on a lighting duty ratio adjusted for individual backlight while the drive current remains constant.
Patent Document 1 also describes to select and use a combination from a number of combinations of the lighting duty ratio and the drive current (peak current) with which the average luminance of the screen is almost the same, according to the speed of the motion on the screen. Specifically, if the speed of the motion on the screen is fast, the scan effect is exhibited by using a substantially large peak current and adjusting the luminance within a range of small lighting duty ratios, and if the speed of the motion on the screen is slow, the luminous efficiency is improved by using a substantially small peak current and adjusting the luminance within a range of large lighting duty ratios.